body{
    height: 3000px;
}
.credential img{
    width: 200px;
    height: 150px;
    float: left;
    margin-left: 90px;
    margin-top: 140px;
}
.credential img:hover{
    transition: all 2s;
    transform:scale(2);
}
.bookrack{
    background-image: url("../resource/images/bookrack.jpg");
    top:200px;
    position: absolute;
    left:251px;
    width: 1000px;
    height: 950px;
}
.credential_classify{
    top:200px;
    position: absolute;
    width: 251px;
    height: 730px;
}
.credential_classify p{
    color: green;
    font-family: 华文琥珀;
    font-size: 40px;
    margin-top: 180px;
}
.credential_classify p:hover{
    color: red;
    font-family: 宋体;
    transition: all 2s;
    cursor: default;
}